1366403989 has 4 divisors (see below), whose sum is σ = 1366482700. Its totient is φ = 1366325280.

The previous prime is 1366403953. The next prime is 1366404001. The reversal of 1366403989 is 9893046631.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 353064100 + 1013339889 = 18790^2 + 31833^2 .

It is a cyclic number.

It is not a de Polignac number, because 1366403989 - 2⁷ = 1366403861 is a prime.

It is a super-2 number, since 2×1366403989² = 3734119722310224242, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1366403939) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 582 + ... + 52279.

It is an arithmetic number, because the mean of its divisors is an integer number (341620675).

Almost surely, 2^1366403989 is an apocalyptic number.

It is an amenable number.

1366403989 is a deficient number, since it is larger than the sum of its proper divisors (78711).

1366403989 is an equidigital number, since it uses as much as digits as its factorization.

1366403989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78710.

The product of its (nonzero) digits is 839808, while the sum is 49.

The square root of 1366403989 is about 36964.9021235009. The cubic root of 1366403989 is about 1109.6679441244.

The spelling of 1366403989 in words is "one billion, three hundred sixty-six million, four hundred three thousand, nine hundred eighty-nine".